PHY 121
Your 'cq_1_09.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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A ball accelerates uniformly as it rolls 20 cm down a ramp, starting from rest, in 2 seconds.
• What are its average velocity, final velocity and acceleration?
answer/question/discussion: ->->->->->->->->->->->-> : vAve = 20/2 = 10cm/s. vf = 20cm/s. a = 10cm/s^2
• If the time interval is in error so that it is 3% longer than the actual time interval, then what are the actual values of the final velocity and acceleration?
answer/question/discussion: ->->->->->->->->->->->-> : time would be 2.06 seconds. vAve = 9.7cm/s, vf = 19.4cm/s, a = 9.4 cm/s^2.
• What is the percent error in each?
answer/question/discussion: ->->->->->->->->->->->-> : vf = |10- 9.7|/9.7 * 100% = 3%. A = |10cm/s^2 – 9.4cm/s^2|/9.4 *100 = 6%
• If the percent error is the same for both velocity and acceleration, explain why this must be so.
• If the percent errors are different explain why it must be so.
answer/question/discussion: ->->->->->->->->->->->-> : The percent error is the same for velocity because it was calculated directly from the quantity that changed by 3% (the time). However, the % error for acceleration is different because it is calculated based on the velocity’s change, which has secondarily been influenced by the change in time.
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10 mins
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Not sure about the last question.
I thought your answer was very good. The link is just included so you can take a minute to check out the way I put it, but no revision is necessary unless you have questions.
&#Please compare your solutions with the expanded discussion at the link
Solution
Self-critique your solutions, if this is necessary, according to the usual criteria. Insert any revisions, questions, etc. into a copy of this posted document. Mark any insertions with &&&& so they can be easily identified. &#